JPH06306008A - Method to manufacture carboxylic acid halogenide and carboxylic acid salt simultaneously - Google Patents

Abstract

Described is a process for the preparation of halides and salts of carboxylic acids by the reaction of metal halides or "onium" halides with carboxylic anhydrides. The process is highly suitable for processing anhydrous spent catalyst preparations. The halide or salt of a carboxylic acid which has been prepared can be used as acylating reagent or alkylating reagent. Metal halide or "onium" halide liberated in this process can be regenerated by re-reacting with carboxylic anhydride. This allows hydrolysis-free alkylation of acylation to be effected without obtaining salt-type waste products. If the mixture of halide and salt of carboxylic acid is reacted with an alcohol, preferably in situ, the resulting esters may be isolated without hydrolysis.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a carboxylic acid halide and a carboxylic acid salt.

[0002]

BACKGROUND OF THE INVENTION Carboxylic acid halides such as trifluoroacetyl chloride, trifluoroacetyl bromide or trifluoroacetyl iodide are important intermediate products in chemical synthesis, for example in the preparation of herbicides, surfactants and pharmaceuticals. It is a thing. For example, trifluoroacetyl chloride is a polymerization initiator for tetrafluoroethylene.

Carboxylates are also important intermediates in the synthesis. That is, the halogen-substituted aromatic compound is reacted with sodium trifluoroacetate under the decomposition and decarboxylation of sodium chloride and converted into the corresponding trifluoromethylated aromatic compound.

The industrial process for producing trifluoroacetic acid chloride is described in International Publication No. WO 81/01406.
No. In this case, 1.1.1. -Trifluor-2.2.2. -Trichloroethane is reacted with sulfur trioxide in the presence of mercury salts and additionally with boron halides and / or halogen sulfonic acids.
The CF ₃ C (O) Cl formed can be converted into an ester of trifluoroacetic acid, for example by reacting with an alcohol. The carboxylic acid bromide and the carboxylic acid iodide can be obtained from the respective carboxylic acid chlorides using anhydrous hydrogen bromide or hydrogen iodide. RN Haszeldin
e, J. Chem. Soc. 1951, pp. 584-587. Another method for producing trifluoroacetyl bromide and trifluoroacetyl iodide is disclosed in Japanese Patent Application Laid-Open No. Hei 2
No. 262530. In this process, the corresponding acetyl fluoride is reacted with lithium bromide or lithium iodide. Furthermore, it is known to produce trifluoroacetyl halides by reacting trifluoroacetic anhydride with phosphoric acid chloride. In this case, a mixed anhydride of phosphonic acid or phosphinic acid and trifluoroacetic acid is produced as a by-product, which anhydride is of no industrial value. This method is described by J. Helinski et al., Phosphorus Sulfur.
Silicon Relat. Chem. 54 (1990), Nos. 225 to 226
Page.

In particular, the known processes for producing carboxylic acid halides form wastes which are difficult to carry out industrially or are undesired.

[0006]

The object of the present invention is, in particular, to carry out an industrially simple process for producing carboxylic acid halides, which in particular ensures the production of carboxylic acid halides without waste. It is to describe the possible methods.

[0007]

This problem is solved by the process according to the invention for the simultaneous production of carboxylic acid halides and carboxylic acid salts. According to the present invention, a carboxylate anion and a 1 / n cation (provided that
Mn ⁺ is in particular a cation of a metal of the first, second or third main group or is an “onium” cation,
A method for simultaneously producing a carboxylic acid halide and a carboxylic acid salt formed from n ⁺ is a positive charge of a cation is a compound Mn ⁺ (Hal ~) n (provided that
Hal ~ represents chloride, bromide or iodide) and is reacted with a carboxylic acid anhydride.
The term "carboxylic acid halide" refers within the scope of the present invention to carboxylic acid halides, carboxylic acid bromides or carboxylic acid iodides, in particular carboxylic acid chlorides.

Preference is given to using, for example, n equivalents of carboxylic anhydride or a slight excess. Of course, in the case of reduced yields, the carboxylic acid anhydride can also be used in deficient amounts. Good results are 0.95n to 1.05
This is achieved when using n equivalents of carboxylic acid anhydride. For example, 1 mol of AlCl ₃ (n = 3) can be converted to acetyl chloride and aluminum acetate by reacting with 3 mol of acetic anhydride.

Preferred metal cations are of the first main group, the second
Of the main and third main groups, especially sodium, potassium and aluminium. In the case of the present invention, "n"
Is an integer, in particular 1, 2 or 3.

The concept of "onium" cation refers to a molecule having a positively charged nitrogen atom.

One preferred property of the process according to the invention is that the valuable product is formed exclusively without producing waste.

According to one preferred embodiment, the starting material Mn ⁺ (Hal ~) n is used in the form of anhydrous waste,
In this case, for example, the starting materials are produced by chemical or physical methods. "Onium" halides are used, for example, as catalysts or phase transfer catalysts, for example in the production of organic carbonates from organic acids, carbon monoxide and oxygen, in the presence of other catalytically active substances. "Onium" halides are also formed, for example, during the base-catalyzed reaction of C-H-acid compounds such as malonic esters with carboxylic acid halides. Metal halides contaminated with organic substances, such as sodium chloride, are waste products when the sodium salt of a carboxylic acid is reacted with, for example, a halogenated aromatic compound to convert it to an alkylated aromatic compound. Wastes of this kind or used catalysts are, according to the process according to the invention,
It can be turned into a valuable product.

According to one variant of the method according to the invention:
Isolation of carboxylic acid halides and carboxylic acid salts is unnecessary. In this variant, the reaction mixture containing the carboxylic acid halide and the carboxylic acid salt is worked up without isolation, for example into the carboxylic acid ester. See below.

According to another variant of the process according to the invention, the reaction mixture is separated into carboxylic acid halides and carboxylic acid salts. This is very easily possible by evaporating the volatile carboxylic acid halide, if desired in a vacuum. Furthermore, the reaction product can be fed to the desired use.

From the above description, the reaction product obtained in the reaction of a metal- or "onium" halide with a carboxylic acid anhydride is again a metal- or "onium".
It has been found that it can be used in such processes as to liberate halides, ie in the case of acylation, alkylation, esterification or in the production of ketones. The halide liberated in this case can be reacted again with the carboxylic acid anhydride and regenerated again. In this way it is possible to produce acylations, alkylations, esterifications or ketones, in which waste salts are unnecessary and in some cases no hydrolysis is necessary. The above-described embodiment of the process according to the invention is particularly advantageous, and in such a way that Mn ⁺ (Hal ~) n is again liberated, which is again reacted with the carboxylic acid anhydride and regenerated in that case. Characterized by the use of halides and / or carboxylates. Thus, continuous or semi-continuous processes are possible without salt formation. Moreover, in this case a working method which is still hydrolysis-free is possible.

In principle, the process according to the invention is suitable for reacting any halide with any carboxylic acid anhydride. In some cases, anhydrides such as hydrocarbons or solvents for the ethers of the monomers, oligomers or polymers must be used in order to increase the reaction rate, or solvents for the halides such as the known polar solvents. One of these, such as nitrile, lactam,
You must use ether etc. In some cases, the reaction rate can also be enhanced by using a phase transfer catalyst such as crown ether.

Very good results are achieved when using carboxylic acid anhydrides of carboxylic acids having 2 to 4 C atoms. With particular preference 1 to 7 halogen atoms,
Especially 2-4 substituted by 1-7 fluorine atoms
Carboxylic anhydrides of carboxylic acids having 1 C atom are used, for example trifluoroacetic anhydride.

As halides, in particular sodium or potassium halides or nitrogen "onium" halides are used. Halide represents especially chlorine, bromine and iodine, especially chlorine and bromine. Particularly good results with surprisingly high yields are:
This is achieved when using "onium" halides in the process according to the invention. Therefore, Mn ⁺ is especially represented by the formula: R ¹ R ² R ³ R ⁴ N ⁺ [wherein R ¹ , R ² , R ³ and R ^{4 are}
Are each independently a hydrogen atom, an alkyl group having 1 to 20 C atoms, an aryl group or an aralkyl group, or R ¹ and R ² , or R ³ and R ⁴ , or R ¹ , R ² and R ³ , or R ¹ , R ² , R ³ and R ⁴
Represents a "onium" cation of the nitrogen atom of a saturated or unsaturated ring system, optionally containing a nitrogen atom, in particular forming a heteroaromatic compound. In this case, the aryl radical represents a phenyl radical and a phenyl radical substituted by one or more halogen atoms and / or by one or more C ₁ -C ₂ -alkyl radicals. Highly preferred is when Mn ⁺ is ammonium, piperidinium, pyridinium or R ¹ ′ R ² ′.
R ^{3'R 4'N + [where, R 1 ', R 2'} , R 3 ' and R ⁴
′ Represents, independently of each other, a hydrogen atom, an alkyl group having 1 to 15 C atoms or a benzyl group]. Good examples include pyridinium hydrohalides, anilinium hydrohalides, piperidinium hydrohalides, benzyltriethylammonium hydrohalides and triethylammonium hydrohalides, especially chlorides and bromides, especially chlorides.

One particularly preferred variant of the invention provides for reacting a mixture of a carboxylic acid halide and a carboxylic acid salt with an alcohol during or after its preparation, forming a carboxylic acid ester. . Many esters of carboxylic acids are industrially used as such.
Acetic acid esters and other carboxylic acid esters are used, for example, as solvents or cleaning agents, for example another ester of succinic acid is used for aromatization. Trifluoroacetic acid ethyl ester is a solvent for the chlorination of paraffins or the polymerization of olefin oxides, for example. Many carboxylic acid esters are also intermediate products in chemical synthesis. Trifluoroacetic acid methyl ester and trifluoroacetic acid-1.1.1-trifluoroethyl ester supply trifluoroethanol after hydrogenation. Trifluoroethanol is used as a solvent and an intermediate product, for example in the production of the solvent and the anesthetic isoflurane. The ester of trifluoroacetic acid is CF
It is also used to introduce or manufacture biologically effective compounds having ₃ groups. For example, N-acylation with trifluoroacetic acid methyl ester can produce peptides with hormonal activity. Trifluoroethyl ester, along with camphor derivatives, supplies the shift reagent for NMR analysis. The trifluoromethylphenyl ester supplies the corresponding trifluoroacetylated phenol, which is a synthetic building block for pharmaceuticals after Fries'scher Verschiebung with aluminum chloride. Many other uses of the esters are known to the person skilled in the art, for example in the manufacture of pharmaceuticals, photosensitizers and colorants.

The production of carboxylic acid esters is usually carried out by reacting the corresponding alcohols with carboxylic acids under acid catalysis. In this case, the water of reaction formed must be removed due to the equilibrium shift; in the case of fluorinated derivatives, this means that the water (at the carbonyl function as the hydrate) is Difficulties due to favorable bonding. It is also already known that carboxylic acid esters can be prepared from carboxylic acid chlorides and alcohols under basic catalysis. However, in this case a post-treatment by hydrolysis is required, and waste salts are produced which have to be disposed of further, for example pyridine hydrochloride. The reaction of a carboxylic acid halide without a base catalyst with an alcohol proceeds at a slight reaction rate.

The invention is based on the recognition that the resulting product mixture containing carboxylic acid halide and carboxylic acid salt supplies the carboxylic acid ester together with the alcohol. In this case, the carboxylate surprisingly exerts a catalytic action.

Of course, the carboxylic acid halide and the carboxylic acid salt can be isolated separately for each difference and then reacted with the alcohol in the desired amount.

The addition of acids, eg carboxylic acids, is possible but not necessary, especially in situ.
This is not advantageous in the case of esterification of.

It is preferable to start with a carboxylic acid chloride for the production of esters. As catalysts, in particular the "onium" salts of carboxylic acids are used.

A variant of the process according to the invention can in principle be used for the preparation of any ester of any carboxylic acid with any alcohol. One preferred embodiment of the variant has the formula R _a C (O) Cl (I) where R _a is an alkyl group having 1 to 6 C atoms; and is substituted by at least one halogen atom. An alkyl group having 1 to 6 C atoms; a phenyl group, a tolyl group;
Representing a phenyl or tolyl group substituted by at least one halogen atom] is provided.

Further, the formula R _b OH (II) [wherein R _b is an alkyl or alkenyl group having 1 to 8 C atoms; 1 to 8 C substituted by at least one halogen atom] An alkyl group or an alkenyl group having an atom; a phenyl group, a tolyl group; a benzyl group; at least 1
Represents a phenyl group, a tolyl group or a benzyl group substituted by 4 halogen atoms and / or at least 1 nitro group].

Particularly preferably, R _a represents an alkyl radical having 1 to 4 C atoms which is substituted by at least one fluorine atom and R _b is an alkyl radical having 1 to 4 C atoms. Group or alkenyl group; alkyl or alkenyl group having 1 to 4 C atoms substituted by at least one halogen atom; phenyl group; substituted by at least one halogen atom and / or at least one nitro group Represents a phenyl group. Particularly, it represents a perfluoromethyl group, a perfluoroethyl group or a perfluoropropyl group. With particular preference R
_b is an alkyl group or an alkenyl group having 1 to 3 C atoms; an alkyl group or an alkenyl group having 1 to 3 C atoms substituted by at least one fluorine atom; a phenyl group; at least one Fluorine atom and /
Or represents a phenyl group substituted by at least one nitro group.

Particularly suitable are the process variants for preparing the esters of acetic acid substituted by one or more fluorine atoms. For example, trifluoroacetic acid phenyl ester can be produced by the method of the present invention. Particularly well suited are 1.1.1-trifluoroethanol, pentafluoropropanol, methanol, ethanol, isopropanol, 4-nitro-phenol,
A process according to the invention for producing an ester of trifluoroacetic acid using pentafluorophenol and allyl alcohol.

The molar ratio of carboxylic acid halide to alcohol is preferably above 0.9. Alcohols can also be used in high excess and are used as solvents, especially where alcohols substituted by electron withdrawing groups, such as fluorine atoms, are important. Advantageously,
The molar ratio of alcohol and carboxylic acid halide is
It is between 0.9: 1 and 5: 1.

The temperature at which the reaction is carried out is the ambient temperature (about 20
C.) to the boiling point of the mixture, for example temperatures up to 100.degree. It is operated at ambient pressure (about 1 bar absolute) or at elevated pressure, for example up to 5 bar absolute.

The alkali metal or "onium" salts are
It can be present in catalytic or molar amounts. Advantageously,
The molar ratio of acid halide to carboxylate is 1: 1 to
It is in the range of 20000: 1.

According to one special embodiment of the invention,
Acid chlorides or acid bromides and alkali metal or "onium" salts of carboxylic acids are prepared in situ. For this purpose, the corresponding alkali metal or "onium" halides, especially chlorides or bromides,
In particular, the chloride is reacted with the anhydride of the carboxylic acid to be used. In the case of this reaction, from the anhydride of the carboxylic acid,
The corresponding acid halide and the corresponding salt are formed. In the case of this embodiment, it is possible to use the halide catalysts used as alkali metal or "onium" halides, which catalysts can be converted in this way into valuable products.

The method according to the invention has a number of advantages. That is, although this method can of course be heated to high temperatures, such as 60 ° C. or higher,
For example, it already proceeds at ambient temperature. Moreover, the use of the process according to the invention makes it possible to produce special acid halides which are difficult to obtain by other processes. Furthermore, the salts produced as wastes in industrial processes can be converted into valuable products. Particularly advantageously, the process according to the invention can be carried out if the salt can be converted into carboxylic acid halides and carboxylic acid salts, the salt can be prepared again during reprocessing and then regenerated by the process according to the invention. Can be used. This method involves, first of all, a number of reactions,
It can be carried out without producing salt waste and / or without the need for hydrolytic work-up.

The process variant according to the invention which uses esterification has the advantage that the carboxylic acid esters can be prepared in an industrially simple manner without further workup by hydrolysis. Esterification in many cases does not produce waste such as pyridine hydrochloride.

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[0036]

【Example】

Example 1: Preparation of trifluoroacetyl chloride and pyridinium trifluoroacetate by reaction of pyridinium hydrochloride with trifluoroacetic anhydride.

Py · HCl + [CF ₃ C (O)] ₂ O −− → CF ₃ C (O) Cl + CF ₃ C (O) O · PyH Pyridinium hydrochloride 2 under exclusion of moisture (N ₂ atmosphere).
6.17 g (0.226 mol) of trifluoroacetic acid 25
61.84 g of trifluoroacetic anhydride
(0.227 mol) was continuously added dropwise at room temperature over 1 hour with stirring. Immediately after adding a few drops of trifluoroacetic anhydride, strong gas evolution could be seen in the reaction flask. The trifluoroacetyl chloride formed was condensed in a cooling gradient cooled to -78 ° C. After the addition of trifluoroacetic anhydride was complete, the reaction solution was heated to 40 ° C. for 1 hour in order to drive out the dissolved trifluoroacetyl chloride. The yield of condensed trifluoroacetyl chloride is 27.95 g (92.5% of theory). By measuring chloride, the residual chlorine content in the reaction solution was found to be 626.2 mg (17.
66 mmol). From this it can be seen that the conversion yield is> 99%.

The reaction residue contained pyridinium trifluoroacetate as well as some trifluoroacetic acid, which was separated by spray drying.
The example was repeated several times for large-scale production.

Example 2: Preparation of trifluoroacetyl chloride and piperidinium trifluoroacetate by reaction of piperidinium hydrochloride with trifluoroacetic anhydride.

Pip · HCl + [CF ₃ C (O)] ₂ O −− → CF ₃ C (O) Cl + CF ₃ C (O) O · PipH Piperidinium hydrochloride 2 under the exclusion of moisture (N ₂ atmosphere).
7.26 g (0.226 mol) of trifluoroacetic acid 25
61.84 g of trifluoroacetic anhydride
(0.227 mol) was continuously added dropwise at room temperature over 1 hour with stirring. Immediately after adding a few drops of trifluoroacetic anhydride, strong gas evolution could be seen in the reaction flask. The trifluoroacetyl chloride formed was condensed in a cooling gradient cooled to -78 ° C. After the addition of trifluoroacetic anhydride was complete, the reaction solution was heated to 40 ° C. for 1 hour in order to drive out the dissolved trifluoroacetyl chloride. The yield of condensed trifluoroacetyl chloride is 26.97 g (89.9% of theory). By measurement of chloride, the residual chlorine content in the reaction solution was 778.8 mg (21.
97 mmol). From this, the conversion yield is found to be> 99.8%.

Example 3: Preparation of trifluoroacetyl chloride and benzyltriethylammonium trifluoroacetate by reaction of benzyltriethylammonium hydrochloride with trifluoroacetic anhydride.

(C ₆ H ₅ CH ₂ ) Et ₃ N.Cl + [CF ₃ C (O)] ₂ O − →→ CF ₃ C (O) Cl + CF ₃ C (O) O · NEt ₃ (C ₆ H ₅ CH ₂ ) 43.55 g (0.191 mol) of benzyltriethylammonium hydrochloride was placed in 21 ml of trifluoroacetic acid under exclusion of moisture (N ₂ atmosphere), and 52.20 g (0.249 mol) of trifluoroacetic anhydride was added. It was added dropwise at room temperature continuously with stirring for 1 hour. Immediately after adding a few drops of trifluoroacetic anhydride, strong gas evolution could be seen in the reaction flask. The trifluoroacetyl chloride formed was condensed in a cooling gradient cooled to -78 ° C. After the addition of trifluoroacetic anhydride was complete, the reaction solution was heated to 40 ° C. for 1 hour in order to drive out the dissolved trifluoroacetyl chloride. The yield of condensed trifluoroacetyl chloride is 2
It is 0.26 g (80.1% of theory). By measuring chloride, the residual chlorine content in the reaction solution was determined to be chloride 15.
It was found to be 3 mg (0.432 mmol).
From this, the conversion yield is found to be 87.1%.

Example 4: Preparation of trifluoroacetyl chloride and triethylammonium trifluoroacetate by reaction of triethylammonium hydrochloride with trifluoroacetic anhydride.

Et ₃ N.HCl + [CF ₃ C (O)] ₂ O −− → CF ₃ C (O) Cl + CF ₃ C (O) O · NHEt ₃ Triethylammonium under the exclusion of moisture (N ₂ atmosphere). 31.11 g (0.226 mol) of the hydrochloride salt was placed in 25 ml of trifluoroacetic acid and trifluoroacetic anhydride 61.
84 g (0.294 mol) were continuously added dropwise at room temperature over 1 hour with stirring. Immediately after adding a few drops of trifluoroacetic anhydride, strong gas evolution could be seen in the reaction flask. The trifluoroacetyl chloride formed was condensed in a cooling gradient cooled to -78 ° C. After the addition of trifluoroacetic anhydride was complete, the reaction solution was heated to 40 ° C. for 1 hour in order to drive out the dissolved trifluoroacetyl chloride. The yield of condensed trifluoroacetyl chloride is 19.82.
g (66.1% of theory). The residual chlorine content in the reaction solution was determined to be 1.16 g of chloride by measurement of chloride.
It was found to be (32.7 mmol). From this, the conversion yield is 77. It turns out to be%.

Example 5: Preparation of trifluoroacetyl bromide and pyridinium trifluoroacetate by reaction of pyridinium hydrobromide with trifluoroacetic anhydride.

Py · HBr + [CF ₃ C (O)] ₂ O − →→ CF ₃ C (O) Br + CF ₃ C (O) O · PyH Pyridinium hydrobromic acid under the exclusion of moisture (N ₂ atmosphere). 36.16 g (0.226 mol) of salt was placed in 25 ml of trifluoroacetic acid to give 61.84 of trifluoroacetic anhydride.
g (0.294 mol) was continuously added dropwise at room temperature over 1 hour with stirring. Immediately after adding a few drops of trifluoroacetic anhydride, strong gas evolution could be seen in the reaction flask. The trifluoroacetyl chloride formed was condensed in a cooling gradient cooled to -78 ° C. After the addition of trifluoroacetic anhydride was complete, the reaction solution was heated to 40 ° C. for 1 hour in order to drive out the dissolved trifluoroacetyl bromide. The yield of condensed trifluoroacetyl bromide is 28.18 g (70.5% of theory). By measuring bromide, the residual bromine content in the reaction solution was determined to be 4.90 g (61.3 g) of bromide.
Was found to be From this, the conversion yield is found to be 96.7%.

Example 6: Preparation of trifluoroacetyl chloride and sodium trifluoroacetate by reaction of sodium chloride with trifluoroacetic anhydride in the presence of crown ether.

NaCl + [CF ₃ C (O)] ₂ O −− → CF ₃ C (O) Cl + CF ₃ C (O) O.Na 13.25 g (0.226 mol) and 18 NaCI under exclusion of moisture. -Crown-6 1.03 g (0.00
4) mol was placed in 25 ml of trifluoroacetic acid, and 32 ml (0.227 mol) of trifluoroacetic anhydride was added dropwise at room temperature with stirring. The trifluoroacetyl chloride formed was condensed in a cooling gradient cooled to -78 ° C. After the addition of trifluoroacetic anhydride was completed,
Stir at room temperature for about 42 hours. The yield of trifluoroacetyl chloride condensed in the cooling gradient was 28.29 g.
(55.90% of the theoretical value). The residual chlorine content in the reaction solution was determined to be 2.95 g of chloride by measurement of chloride.
It was found to be (83.2 mmol). From this, the conversion yield is found to be 63.3%.

Example 7: Preparation of trifluoroacetyl iodide and sodium trifluoroacetate by reaction of sodium iodide with trifluoroacetic anhydride.

NaI + [CF ₃ C (O)] ₂ O −− → CF ₃ C (O) I + CF ₃ C (O) O.Na 34.00 g (0.22 g of sodium iodide under the exclusion of moisture).
7 mol) and 18-crown-6 1.03 g (0.
004 mol) in 25 ml trifluoroacetic acid and 32 ml (0.227 mol) trifluoroacetic anhydride were added dropwise at room temperature with stirring. The solution solidified in the reaction flask immediately after the addition of a few drops of trifluoroacetic anhydride. Therefore, 25 ml of trifluoroacetic acid was added again. The produced trifluoroacetyl iodide was heated at -78 ° C.
It was condensed in a cooling gradient cooled to. After the addition of trifluoroacetic anhydride was complete, stirring was continued for about 16 hours at room temperature. The next day, the reaction flask was placed in a water bath with hot water at 50 ° C for about 8 hours, whereupon the temperature in the reaction flask rose to 40 ° C. The yield of trifluoroacetyl iodide is 17.23 g (33.90% of theory). Measurement of iodide revealed that the residual iodine content in the reaction solution was 11.17 g (74.5 mmol) iodide. From this, the conversion yield is found to be 50.5%.

Example 8: Preparation of trifluoroacetyl iodide and potassium trifluoroacetate by reaction of potassium iodide with trifluoroacetic anhydride.

KI + [CF ₃ C (O)] ₂ O −− → CF ₃ C (O) I + CF ₃ C (O) O · K 37.48 g (0.226 g) of potassium iodide under the exclusion of moisture.
Mol) and crown ether 0.99 g (0.00
4 mol) in 25 ml of trifluoroacetic acid and 32 ml (0.227 mol) of trifluoroacetic anhydride were added dropwise at room temperature with stirring. The resulting trifluoroacetyl iodide was condensed in a cooling gradient cooled to -78 ° C. After the addition of trifluoroacetic anhydride was completed,
Stir for about 12 hours at room temperature. The next day, the reaction flask was placed in a water bath with hot water at 40 ° C. for about 10 hours. The yield of trifluoroacetyl iodide is 20.06g.
(39.40% of theoretical value). According to the measurement of iodide, the residual iodine content in the reaction solution was 2.60 g of iodide.
(21.0 mmol). From this, the conversion yield is found to be 43.9%.

Example 9: Preparation of acetyl chloride and pyridinium acetate by reaction of acetic anhydride with pyridinium chloride.

Py.HCl + [CH ₃ C (O)] ₂ O −− → CH ₃ C (O) Cl + CH ₃ C (O) O · PyH Pyridinium chloride 45 in a Claisen device under the exclusion of moisture. 0.33 g (0.392 mol) of acetic acid 30
36 ml (0.381 mol) of acetic anhydride were combined at room temperature with stirring. Continue to 100 in the ice bath
Heated to ℃ and raised the temperature to 170 ℃ in 7 hours. The acetyl chloride formed was collected in a receiver cooled to 10 ° C. along with anhydride and acetic acid which were also overflowed. The yield of acetyl chloride isolated in the receiver was 7.1% of theory after this reaction time. Conversion rate is about 1
It was 0%.

In Examples 6-8, 18-crown-6
It was used. The reactions described in these examples proceed without the addition of crown ethers, but at significantly lower reaction rates.

Example 10: Preparation of trifluoroacetyl chloride and aluminum trifluoroacetate by reaction of aluminum trichloride with trifluoroacetic anhydride.

AlCl₃+3 (CF₃CO)₂O ---> 3CF₃COCl + Al (OCOCF ₃ )₃ AlCl under the exclusion of moisture (N2 atmosphere)₃39.2g
(0.294 mol) in 147 ml of 1,4-dioxane
And then sequentially for 3 days to all trifluoroacetic anhydride.
At 185.25 g (0.882 mol) (Al per day
Cl₃To (CF₃CO)₂O) while stirring
The solution was continuously added dropwise at room temperature over 1 hour. Trifluoroacetic acid
Immediately after adding a few drops of anhydrous gas into the reaction flask.
We were able to confirm the occurrence. Trifluoro generated
Acetyl chloride in a cooling gradient cooled to -78 ° C
Condensed. The addition of trifluoroacetic anhydride is complete
Later, ejected the dissolved trifluoroacetyl chloride
The reaction solution was heated to 40 ° C. for 2 hours in order to be activated.
Isolation of condensed trifluoroacetyl chloride
The total yield was 111.72 g over all 3 days,
This corresponds to 95.9% of theory.

Example 11: Trifluoroacetyl chloride and 2, in the presence of pyridinium trifluoroacetate
Trifluoroacetic acid by reaction with 2,2-trifluoroethanol - preparation of trifluoroethyl ester _{PyTFA CF 3 COCl + CF 3 CH} 2 OH --- → CF 3 COOCH 2 CF 3 + HCl laboratory circulation unit (KPG as receiver 1 l four-necked flask with stirrer, prominent-pump (Promin
ent-Pumpe), 30 cm with a filled Raschig ring
Column) and 30 g (0.16 mol) of the pyridinium trifluoroacetate obtained in Example 1 in 355 g (3.55 mol) of 2,2,2-trifluoroethanol are circulated at an internal temperature of 54 ° C. It was stirred while being allowed to. Subsequently, 134 g (1.01) of trifluoroacetyl chloride obtained in the same manner as in Example 1 was placed in a flask through a dip tube.
Mol) in 100 minutes. After the addition of trifluoroacetyl chloride was completed, the reaction was carried out for 10 minutes. Subsequently, the reaction mixture was mixed with a Vigreu column (Vigreu
Fractional distillation via xkolonne (transition temperature: 54-56 ° C.) gives 177.8 g of trifluoroacetic acid-trifluoroethyl ester, which corresponds to a yield of 89.8% of theory. . The trifluoroethanol / pyridinium salt mixture remaining in the receiver flask can again be used for esterification with the same efficiency.

Examples 12 to 17: Preparation of trifluoroacetic acid ester by reaction of trifluoroacetyl chloride with methanol, ethanol, isopropanol, 4-nitrophenol, pentafluorophenol and allyl alcohol in the presence of pyridinium trifluoroacetate. In the same manner as in the method of 11, trifluoroacetyl chloride, methanol (94%), ethanol (96
%), Isopropanol (89%), 4-nitro-phenol (85%), pentafluorophenol (92)
%) And allyl alcohol (81%) were also prepared.

Example 18: Preparation of trifluoroacetic acid-1.1.1-trifluoroethyl ester in the presence of piperidinium trifluoroacetate. Starting from trifluoroacetic anhydride and piperidinium chloride in analogy to example 2. To produce and isolate trifluoroacetyl chloride and piperidinium trifluoroacetate. Next, in the same manner as in Example 11, trifluoroacetic acid-1.1.1-trifluoroethyl ester was produced.

Example 19: Preparation of trifluoroacetic acid-trifluoroethyl ester by reaction of trifluoroacetic anhydride with 2,2,2-trifluoroethanol in the presence of pyridinium hydrochloride ("in situ"). the method of ") Py · HCl + (CF 3 CO) 2 O + CF 3 CO 2 ~ · PyH + CF 3 COCl CF 3 CH 2 OH ------- → CF 3 CO-OCH 2 CF 3 + PyTFA + HCl KPG stirrer, dry ice 2 with condenser and dropping funnel
Pyridinium hydrochloride 2 in a 50 ml three neck flask
3.11 g (0.2 mol) and 2,2,2-trifluoroethanol 20.0 g (0.2 mol) were charged.
Subsequently, 42.01 g (0.2 mol) of trifluoroacetic anhydride was added dropwise at an internal reaction temperature of 52 to 55 ° C. over 3 hours. The yield of trifluoroacetic acid-trifluoroethyl ester was 98% (GC).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Stefan Palshelm, Federal Republic of Germany Barsinghausen Bekestraße 10 (72) Inventor, Kerstin Eichholtz, Federal Republic of Germany Langenhagen Im Kolling Small 38

Claims (12)

[Claims] 1. Carboxylate anions and 1 / n cations, where Mn ⁺ is in particular a cation of a metal of the first, second or third main group or an "onium" cation. Wherein n ⁺ is the positive charge of the cation) and a compound Mn ⁺ (H
al-) n (where Hal-represents chloride, bromide or iodide) with a carboxylic acid anhydride, for the simultaneous production of a carboxylic acid halide and a carboxylic acid salt. 2. Mn ⁺ (Hal ~) n is replaced by Mn ⁺ (Hal ~) n
A process according to claim 1, which is used in the form of an anhydrous waste containing, for example, the used catalyst preparation. 3. The method according to claim 1, wherein a carboxylic acid anhydride of a carboxylic acid having 2 to 4 C atoms is used. 4. A carboxylic acid anhydride having 2 to 4 C atoms, which is substituted by 1 to 7 halogen atoms, in particular fluorine atoms, is used. The method described in. 5. The method according to claim 1, wherein Mn ⁺ represents Na ⁺ , K ⁺ or an “onium” cation of a nitrogen atom. 6. Mn ⁺ has the formula: R ¹ R ² R ³ R ⁴ N ⁺ [wherein
R ¹ , R ² , R ³ and R ⁴ independently of one another are a hydrogen atom, 1
Represents an alkyl, aryl or aralkyl group having from 20 C atoms, or is R ¹ and R ² , or R ³ and R ⁴ , or R ¹ , R ² and R ³ , or R ¹ , R ² , R ³ and R ⁴ form a saturated or unsaturated ring system, optionally containing a nitrogen atom], the process according to claim 5, wherein 7. Mn ⁺ is an ammonium, piperidinium, pyridinium or ^{R 1'R 2'R 3'R 4} 'N + ^{[where, R 1 ', R 2'} , R 3 ' and R ^4' are each Independently represent a hydrogen atom, an alkyl group having 1 to 15 C atoms, or a benzyl group]. 8. The method according to claim 1, wherein the halide represents chloride. 9. A reaction mixture containing a carboxylic acid halide and a carboxylic acid salt is used in an acylation process,
Method according to any one of claims 1-8. 10. The method according to claim 1, wherein the reaction mixture is separated into a carboxylic acid halide and a carboxylic acid salt. 11. A carboxylic acid halide or a carboxylic acid salt is used as an acylating reagent or an alkylating reagent, and the liberated Mn ⁺ (Hal ~) n is reacted again with the carboxylic acid anhydride and regenerated in that case. , Claims 1 to 1
The method according to any one of 0 to 0. 12. A process according to claim 1, wherein a mixture of carboxylic acid halide and carboxylic acid salt is reacted with an alcohol during or after its preparation to form a carboxylic acid ester.